Today's electronic devices, from computers to cars to rockets to watches, are built by connecting together anywhere from a few to millions of electrical components. While complex electronic devices can indeed contain millions of components, only a relatively small number of these components are truly different from other types of components. Beginning electrical engineers learn all about the different types of components, since they are indeed the building blocks of all electronic circuitry, from simple to complex.
The following four types of components are such essential building blocks they can be found in almost any electrical circuit: the resistor, the capacitor, the transistor, and the diode. A diode is considered an essential building block since it assures that electricity flows in only an intended direction and not in an unintended direction. Without diodes, most electronic devices simply would not operate.
While diodes are indeed an essential part of most electronic devices, they are not without their problems. One such problem is that diodes typically require a forward voltage of approximately 0.7 Volts to operate, and diodes dissipates power in proportion to this forward voltage. While many household electronic devices such as televisions, microwave ovens, and the like that are powered by household voltage can tolerate the power loss of the diodes in the circuit, this power loss is not tolerated as well by battery powered electronic devices, such as calculators, tape players, handheld video games, and portable computers. For these devices, this power loss directly translates into shorter battery life. This shorter battery life can directly impact the usability of the device.
One such attempt at making a low power diode is disclosed in U.S. Pat. No. 3,599,323. The diode in this patent is a hot carder diode specially fabricated by depositing vaporized chromium onto a prepared P-type silicon surface. Current flow is by the Schottky emission of hot holes from silicon over the relatively low barrier at the chromium-silicon interface. While the diode of this patent is able to reduce power loss by reducing the forward voltage from 0.7 Volts to approximately 0.3 Volts, it is expensive and complex to make. In addition, significant power is still lost from this diode even at a 0.3 volt forward voltage, making it undesirable for battery powered electronic devices or other devices with low power requirements.